Fixture for a dental implant and an implant system comprising the same

ABSTRACT

A dental implant fixture comprises: a body; a continuous thread part including a continuous thread continuously formed in a spiral shape along an outer circumferential direction of the body; a bone damage prevention part formed at one end portion of the body and preventing an alveolar bone existing in an opening area of a hole where the body is implanted from being damaged due to the continuous thread part; and an entrance guide part provided at the other end portion of the body and guiding the body in an initial implantation entrance direction. The entrance guide part comprises; a flat portion of horizontal flat; an inclined portion extending upward from a circumferential surface of the flat portion with an upwardly increasing radius; and a rounded portion connecting the inclined portion and the continuous thread part and having at least one area inwardly rounded toward the centerline of the fixture.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of U.S.application Ser. No. 13/642,570, filed on Oct. 22, 2012, which is aNational Stage of International Application No. PCT/KR2010/009603, filedon Dec. 30, 2010, which claims priority to and the benefit of KoreanApplication No. 10-2010-0037567, filed on Apr. 22, 2010, in the KoreanIntellectual Property Office, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a dental implant fixture and animplant system having the same, and more particularly, to an implantsystem with which an implant surgery may be conveniently performedbecause another fixture may be used without additional drilling whenimplantation of a first fixture fails.

BACKGROUND ART

In principle, an implant means a substitute configured to restoredamaged human tissue. However, in dentistry, an implant means a seriesof medical procedures for implanting an artificial tooth. In the medicalprocedures, a fixture, which is a dental root formed of suchrejection-free material as titanium to replace a damaged dental root, isimplanted into an alveolar bone where a tooth was pulled out, and then adental implant is fixed to restore functions of the tooth.

Typical prostheses or dentures may hurt adjacent teeth and bones withtime. However, an implant does not hurt adjacent tooth tissue, and maybe used semi-permanently since it causes no tooth decay while having thesame function and shape as a natural tooth.

In the medical procedures, also referred to as an implant or implantprocedures, a designated drill is used to bore a hole at an implantlocation, and then a fixture is implanted into and osteointegrated withan alveolar bone, although the procedures may be different dependingupon a variety of types of the fixture. Then, in general, an abutment iscoupled with the fixture, and a finishing prosthesis is applied to theabutment to finish the procedures.

An implant may restore a single missing tooth, increase the functions ofthe dentures of a patient with partial or complete anodontia, improvethe appearance of a dental prosthesis, disperse the excessive stressupon adjacent supporting bone tissue, and help stabilize a set of teeth.

In general, such an implant includes a fixture which is an artificialdental root to be implanted, an abutment coupled with the fixture, anabutment screw fixing the abutment to the fixture, and an artificialtooth coupled with the abutment. Here, a healing abutment (not shown)may be coupled with the fixture to maintain the coupled state before theabutment is coupled with the fixture, i.e., until the fixture isosteointegrated with an alveolar bone.

A fixture, which is a part of an implant, is implanted into a drilledhole in an alveolar bone where the medical procedures are to be applied,and acts as an artificial dental root. Therefore, a fixture needs to befirmly implanted in the alveolar bone.

Thus, a thread part (thread) may be disposed on the outer surface of afixture so that the fixture is firmly coupled with the inner sidewall ofan alveolar bone where a drilled hole is formed. The thread part is ledinto the alveolar bone so that the fixture and the alveolar bone arefirmly coupled with each other, and strengthens the force with which thefixture fixes the alveolar bone by increasing the contact area of both.

Meanwhile, as described above, an implant surgery is carried out byforming a hole with a drill in an alveolar bone, implanting a fixture inthe hole, coupling the fixture with an abutment when osteointegrationprogresses, and then applying an artificial tooth to finish theprocedures. In such an implant surgery, fixtures with different sizes(maximum thread diameters) may be used depending upon operationconditions. Then, different drills need to be used. Usually, alarge-scale drill is used for a large fixture, and a small-scale drillis used for a small fixture since the bodies of the fixtures varydepending on the sizes of the fixtures.

However, a cumbersome operation may be entailed when a drillcorresponding to the size of a fixture needs to be selected, or when anadditional boring is required for implanting a larger fixture with ahole for fixture implanting already formed in an alveolar bone.Especially, when another fixture is implanted after an initialimplanting failed, an additional boring with an additional drill isnecessary since the sizes of the bodies of the fixtures are different.Therefore, the development of a new implant system is required for moreconvenient implant procedures.

On the other hand, in a typical conventional dental implant fixture, acertain section of a thread part is discontinued, that is, the threadpart does not continue, and a cutting edge portion is formed in thediscontinued area to make a fixture easily implanted. However, thecutting edge portion formed by discontinuing the thread part maymisalign the fixture with a desired implantation direction and thus asolution for this issue is needed.

Also, in the conventional dental implant fixture, since the thread partis formed across the entire area of an outer surface of a body of thefixture, when an entrance of a hole is relatively narrow, for example, abone (an alveolar bone) existing in an opening area of the hole may bedamaged due to the thread part formed in the entire area of the outersurface of the body. As a result, an implant surgery may fail and thus asolution for this issue is needed.

SUMMARY OF THE INVENTION

The present invention provides an implant system with which an implantsurgery may be conveniently performed because another fixture having adifferent size may be used without additional drilling when implantationof a first fixture fails.

The present invention also provides a dental implant fixture which mayprevent misalignment of a fixture with a desired direction of fixtureimplantation due to a cutting edge portion formed in a conventionalfixture, leading a successful implant surgery, and an implant systemhaving the same.

The present invention also provides a dental implant fixture which mayprevent damage of an alveolar bone existing in an opening area of ahole, in which a fixture is implanted, due to a thread part formedacross the entire area of an outer surface of a body as in aconventional fixture, leading a successful implant surgery, and animplant system having the same.

According to an aspect of the present invention, there is provided animplant system including a first fixture comprising a first body and afirst continuous thread part, the first continuous thread part having aspiral shape and formed on an outer circumferential surface of the firstbody; and a second fixture comprising a second body and a secondcontinuous thread part, the second body having the same shape andstandard as those of the first body, the second continuous thread parthaving a spiral shape and formed on an outer circumferential surface ofthe second body, wherein a diameter of the second continuous thread partis different from a diameter of the first continuous thread part.

An end portion region of the second continuous thread part may beextended further outwardly in a radius direction from a leading endportion of the first continuous thread part by a predetermined length.

The end portion region of the second continuous thread part may beextended further outwardly in a radius direction from a leading endportion of the first continuous thread part by a predetermined lengthidentically to an upper curved surface and a lower curved surface of thefirst continuous thread part.

The first fixture may further include a first bone damage preventionpart formed at one end portion of the first body and preventing analveolar bone existing in an opening area of a hole where the firstfixture is implanted from being damaged due to the first continuousthread part; and the second fixture may further include a second bonedamage prevention part formed at one end portion of the second body andpreventing the alveolar bone existing in the opening area of the holefrom being damaged due to the second continuous thread part

The first and second bone damage prevention parts may be respectivelyprovided in non-threaded regions where the first and second continuousthread parts are not formed at outer surfaces of end portions of thefirst and second bodies and integrally formed in the first and secondbodies by a predetermined length in the one end portion of each thefirst and second bodies.

Each of the first and second bone damage prevention parts may have anon-linear outer surface such that a diameter of each of the first andsecond bone damage prevention parts decreases from one end portion ofeach of the first and second bodies to an opposite side thereof.

The first and second bodies may be provided such that an outside of eachof the first and second bodies is tapered in a manner such that adiameter of each of the first and second bodies deceases along animplantation direction; and an imaginary contour line connecting leadingend portions of the first and second continuous thread parts forms ataper inclination line such that a width between the imaginary contourlines gradually decreases in the implantation direction.

A pitch between threads of the first continuous thread part and a pitchbetween threads of the second continuous thread part may be identical toeach other.

Each of the first and second continuous thread parts may include aleading end portion that is vertical or inclined toward one side; and acurved part formed on an upper or lower surface of the leading endportion and reducing resistance torque, wherein the first fixturefurther comprises a first entrance guide part provided at the other endportion of the first body opposite to the first bone damage preventionpart, and formed as long as a predetermined section in a lengthwisedirection of the first body from the leading end portion of the firstbody with respect to a direction in which the first body is implantedand guiding the first body in an initial implantation entrancedirection, and the second fixture further comprises a second entranceguide part provided at the other end portion of the second body oppositeto the second bone damage prevention part, and formed as long as apredetermined section in a lengthwise direction of the second body fromthe leading end portion of the second body with respect to a directionin which the second body is implanted and guiding the second body in aninitial implantation entrance direction,

According to another aspect of the present invention, there is providedan implant system including a first fixture comprising a first body anda first bone damage prevention part formed at one end portion of thefirst body and preventing an alveolar bone existing in an opening areaof a hole where the first fixture is implanted from being damaged; and asecond fixture comprising a second body that is the same as the firstbody and a second bone damage prevention part formed at one end portionof the second body and preventing the alveolar bone existing in theopening area of the hole from being damaged.

The first fixture may include a first thread part formed in a spiralshape along an outer circumferential direction of the first body, thesecond fixture may include a second thread part formed in a spiral shapealong an outer circumferential direction of the second body, and an endportion region of the second thread part may be extended furtheroutwardly in a radius direction from a leading end portion of the firstthread part by a predetermined length.

The end portion region of the second thread part may be extended furtheroutwardly in a radius direction from a leading end portion of the firstthread part by a predetermined length identically to an upper curvedsurface and a lower curved surface of the first thread part.

The first and second bodies may be provided such that an outside of eachof the first and second bodies is tapered in a manner such that adiameter of each of the first and second bodies gradually deceases alongan implantation direction, and an imaginary contour line connectingleading end portions of the first and second thread parts forms a taperinclination line such that a width between the imaginary contour linesgradually decreases in the implantation direction.

A pitch between threads of the first thread part and a pitch betweenthreads of the second thread part may be identical to each other, andthe first and second thread parts may respectively be first and secondcontinuous thread parts that are continuously formed on the first andsecond bodies.

Each of the first and second bone damage prevention parts may be formedin a non-threaded region of an outer surface of one end portion of eachof the first and second bodies and integrally formed in the first andsecond bodies by a predetermined length in the one end portion of each othe first and second bodies

Each of the first and second bone damage prevention parts may have anon-linear outer surface such that a diameter of each of the first andsecond bone damage prevention parts decreases from one end portion ofeach of the first and second bodies to an opposite side thereof.

According to another aspect of the present invention, there is provideda dental implant fixture including a body: and a continuous thread partcontinuously formed in a spiral shape along an outer circumferentialdirection of the body.

The dental implant fixture may further include a bone damage preventionpart formed at one end portion of the body and preventing an alveolarbone existing in an opening area of a hole where the dental implantfixture is implanted from being damaged due to the continuous threadpart.

The bone damage prevention part may be provided in a non-threaded regionwhere the continuous thread part is not formed at an outer surface of anend portion of the body and integrally formed in the body by apredetermined length in the one end portion of the body.

The bone damage prevention part may be integrally formed in the body bya predetermined length at one end portion of the body.

The bone damage prevention part may have a non-linear outer surface suchthat a diameter of the bone damage prevention part decreases from oneend portion of the body to an opposite side thereof.

The dental implant fixture may further include an entrance guide partprovided at the other end portion of the body opposite to the bonedamage prevention part, and formed as long as a predetermined section ina lengthwise direction of the body from the leading end portion of thebody with respect to a direction in which the body is implanted andguiding the body in an initial implantation entrance direction

The body may be provided such that an outside of the body is tapered ina manner such that a diameter of the body deceases along an implantationdirection, and an imaginary contour line connecting a leading endportion of the continuous thread part forms a taper inclination linesuch that a width between the imaginary contour lines graduallydecreases in the implantation direction.

The continuous thread part may include a leading end portion that isvertical or inclined toward one side; and a curved part formed on anupper or lower surface of the leading end portion and reducingresistance torque, wherein the curved part is an upper or lower curvedpart respectively formed on an upper or lower surface with respect tothe leading end portion.

An abutment coupling part to which an abutment is coupled may beprovided in an inner area of one end portion of the body, and theabutment coupling part may includes: a first recessed part primarilyrecessed from one end of the body in a length direction of the body; asecond recessed part secondarily recessed deeper from the other end ofthe first recessed part in the length direction of the body and has apolygonal shape; and a screw hole formed in a center region of thesecond recessed part in the length direction of the body, to which anabutment screw for coupling with the abutment is coupled.

According to another aspect of the present invention, there is provideda dental implant fixture including a body; and a bone damage preventionpart preventing an alveolar bone existing in an opening area of a holewhere the body is implanted.

The bone damage prevention part may be provided in a non-threaded regionat an outer surface of an end portion of the body and integrally formedin the body by a predetermined length in the one end portion of thebody.

The bone damage prevention part may have a non-linear outer surface suchthat a diameter of the bone damage prevention part decreases from oneend portion of the body to an opposite side thereof.

An abutment coupling part to which an abutment is coupled may beprovided in an inner area of one end portion of the body, and theabutment coupling part may include: a first recessed part primarilyrecessed from one end of the body in a length direction of the body; asecond recessed part secondarily recessed deeper from the other end ofthe first recessed part in the length direction of the body and has apolygonal shape; and a screw hole formed in a center region of thesecond recessed part in the length direction of the body, to which anabutment screw for coupling with the abutment is coupled.

According to another aspect of the present invention, there is provideda dental implant fixture comprising: a body; a continuous thread partincluding a continuous thread continuously formed in a spiral shapealong an outer circumferential direction of the body; a bone damageprevention part formed at one end portion of the body and preventing analveolar bone existing in an opening area of a hole where the body isimplanted from being damaged due to the continuous thread part; and anentrance guide part provided at the other end portion of the body andguiding the body in an initial implantation entrance direction.

The entrance guide part comprises: a flat portion which is horizontalflat; an inclined portion extending upward from a circumferentialsurface of the flat portion with an upwardly increasing radius; and arounded portion connecting the inclined portion and the continuousthread part and having at least one area inwardly rounded toward thecenterline of the fixture.

The bone damage prevention part is provided in a non-threaded regionwhere the continuous thread part is not formed at an outer surface of anend portion of the body.

The bone damage prevention part is integrally formed in the body by apredetermined length at one end portion of the body.

The bone damage prevention part has a non-linear outer surface extendingto a starting point of the continuous thread part, and has a diametergradually decreasing along an implantation direction.

The body is provided such that an outside of the body is tapered in amanner such that a diameter of the body deceases along an implantationdirection, and an imaginary contour line connecting a leading endportion of the continuous thread forms a taper inclination line suchthat a width between the imaginary contour lines gradually decreases inthe implantation direction.

The continuous thread comprises: a leading end portion that is verticalor inclined toward one side; and a curved part formed on an upper orlower surface of the leading end portion and reducing resistance torque.

The curved part is an upper or lower curved part respectively formed onan upper or lower surface with respect to the leading end portion.

An abutment coupling part to which an abutment is coupled is provided inan inner area of one end portion of the body, and the abutment couplingpart comprises: a first recessed part primarily recessed from one end ofthe body in a length direction of the body; a second recessed partsecondarily recessed deeper from the other end of the first recessedpart in the length direction of the body and has a polygonal shape; anda screw hole formed in a center region of the second recessed part inthe length direction of the body, to which an abutment screw forcoupling with the abutment is coupled.

According to the embodiments, although implantation of the first fixturefails, the second fixture may be directly implanted without additionaldrilling. Therefore, an implant surgery may be performed more easily ascompared with the related art.

Also, according to the embodiments, the misalignment of a fixture with adesired direction of fixture implantation due to a cutting edge portionformed in a conventional fixture may be prevented, leading a successfulimplant surgery.

In addition, according to the embodiments, the damage of an alveolarbone existing in an opening area of a hole, in which a fixture isimplanted, due to a thread part formed across the entire area of anouter surface of a body as in a conventional fixture may be prevented,leading a successful implant surgery.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural view of an implant system according toan embodiment of the present invention.

FIG. 2 is an image illustrating states in which four fixtures havingdifferent sizes are implanted in a hole of an alveolar bone of the samediameter.

FIG. 3 is a perspective view schematically illustrating a process ofimplanting the first fixture of the dental implant of FIG. 1.

FIGS. 4 through 7 are respectively a perspective view, a side view, across-sectional view, and a plan view of the first fixture.

FIG. 8 is a partial enlarged view illustrating a continuous thread partof each of the first and second fixtures.

FIG. 9 is a perspective view illustrating an abutment to be coupled tothe first fixture according to an embodiment.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration specific preferredembodiments in which the invention may be practiced. These embodimentsare described in sufficient detail to enable those skilled in the art topractice the invention, and it is understood that other embodiments maybe utilized and that logical structural, mechanical, electrical, andchemical changes may be made without departing from the spirit or scopeof the invention. To avoid detail not necessary to enable those skilledin the art to practice the invention, the description may omit certaininformation known to those skilled in the art. The following detaileddescription is, therefore, not to be taken in a limiting sense, and thescope of the present invention is defined only by the appended claims.

FIG. 1 is a schematic structural view of an implant system according toan embodiment of the present invention. FIG. 2 is an image illustratingstates in which four fixtures having different sizes are implanted in ahole of an alveolar bone of the same diameter. FIG. 3 is a perspectiveview schematically illustrating a process of implanting the firstfixture of the dental implant of FIG. 1.

Referring to FIG. 3 first, a plurality of teeth 12 are arranged along agum 11. The teeth 12 are primary digestive means that break food intosmall pieces before the food is sent to the stomach. Usually, peoplehave twenty eight teeth.

If one of the teeth 12 is lost (for example, a molar is lost), it is notgood for the appearance, as well as it is difficult to chew. Thus, afirst fixture 100 may be implanted in the gum 11 as a substitute for adental root 12 a of the lost tooth 12. If the size of the first fixture100 is not suitable, a second fixture 200 may be implanted. The firstfixture 100 and the second fixture 200 may be formed of titanium (Ti) ora titanium (Ti) alloy that the human body does not reject.

In this way, the first fixture 100 or the second fixture 200, whateverselected as necessary, may be implanted in an alveolar bone inside thegum 11. Drilling is carried out for the initial implantation of thefirst fixture 100. That is a drill hole H is formed in the alveolar boneat a predetermined position.

An implant system according to an embodiment of the present invention isdescribed below with reference to FIGS. 1 and 2. The implant systemaccording to the present embodiment generally includes two fixtures: afirst fixture 100 and a second fixture 200.

As described above, the first fixture 100 is implanted in the drill holeH (refer to FIG. 3) formed in an alveolar bone and the second fixture200 is implanted in the same hole by pulling out the first fixture 100when the first fixture 100 is too large for the hole. Of course, a thirdfixture (not shown), a fourth fixture (not shown), etc. havingrelatively larger sizes than the second fixture 200 may be implanted inthe drill hole H under the same conditions.

In order for the second fixture 200 to be implanted in the same placewhere the first fixture 100 is implanted without additional drilling andalso without damaging an alveolar bone therearound, the first and secondfixtures 100 and 200 may have the conditions in common. As such, in theimplant system according to the present embodiment, the first and secondfixtures 100 and 200 have the same structure except for some portions.Thus, in the following descriptions, while a description about thestructure of the second fixture 200 is largely omitted, the structure ofthe first fixture 100 is mainly described in detail with differencesbetween the first and second fixtures 100 and 200 as necessary.

For reference, the first fixture 100 that is described below may be oneused for an initial implant surgery or may be for emergency use when thefirst fixture 100 is directly implanted in an alveolar bone withoutfilling a damaged portion without a predetermined bone substitutematerial when a surgery fails. This condition also applies to the secondfixture 200.

FIGS. 4 through 7 are respectively a perspective view, a side view, across-sectional view, and a plan view of the first fixture. FIG. 8 is apartial enlarged view illustrating a continuous thread part of each ofthe first and second fixtures. FIG. 9 is a perspective view illustratingan abutment to be coupled to the first fixture according to anembodiment.

Referring to FIGS. 1 and 4 through 9, the first fixture 100 for a dentalimplant as a part of the implant system of the present embodimentincludes a first body 120 having a first bone damage prevention part 170and a first entrance guide part 160 formed at the opposite ends thereofand a first continuous thread part 130 formed in a spiral shape on theouter circumferential surface of the first body 120 to be continuously.

For reference, as illustrated in FIG. 1, like the first fixture 100, thesecond fixture 200 for a dental implant as another part of the implantsystem of the present embodiment also includes a second body 220 havinga second bone damage prevention part 270 and a second entrance guidepart 260 formed at the opposite ends thereof and a second continuousthread part 230 formed in a spiral shape on the outer circumferentialsurface of the second body 220 to be continuously. The first and secondbodies 120 and 220 may be provided to have substantially the same size.

First, the first body 120 constitutes a central stem of the firstfixture 100 of the present embodiment. Since the first fixture 100 isimplanted in the direction of an arrow of FIG. 3, the outside of thefirst body 120 is tapered in a manner such that the diameter of thefirst body 120 deceases along an implantation direction. This conditioncommonly applied to the second body 220 of the second fixture 200.

In the related art, a body of a fixture (not shown) has a cylindricalshape having a uniform diameter. However, in the present embodiment,each of the bodies 120 and 220 of the first and second fixtures 100 and200 is partially tapered in a manner such that the diameter of the firstbody 120 decreases along the implantation direction, therebyfacilitating implantation. The first and second bodies 120 and 220 mayhave the same inclination throughout the entire area of the outersurface thereof or a tapered inclination only in a particular section.In the latter case, a tapered inclination applies to a section from thetop end of each of the first and second bodies 120 and 220 to a middleportion thereof in FIG. 1, whereas the other part may have a linearshape like a cylinder. In this case, initial implantation is made easyand a strong fixing force may be provided.

A bevel part 121 is formed at an edge area of one end of the first body120. The bevel part 121 provides a relatively large contact area than analveolar bone and thus a strong fixing force is provided. Also, a firstabutment coupling part 140, to which an abutment 150 (refer to FIG. 9)is coupled, is provided in an inner area of one end portion of the firstbody 120 where the first bevel part 121 is formed.

With reference to FIG. 9, the abutment 150 will now be describedbriefly. The abutment 150 has a truncated cone shape. The abutment 150includes an abutment body 151 through which a penetration hole 151 a isformed, a first coupling part 152 disposed at a lower end of theabutment body 151, and a second coupling part 153 disposed at a lowerend of the first coupling part 152. The first coupling part 152 may befitted into a first recessed part 141 (described later) of the firstabutment coupling part 140, and the second coupling part 153 may befitted into a second recessed part 142 (described later) of the firstabutment coupling part 140.

Since the first recessed part 141 has a tapered inner wall as describedbelow, the outer surface of the first coupling part 152 of the abutment150 is also tapered. The second coupling part 153 has a shapecorresponding to the shape of the second recessed part 142.

In detail, the first abutment coupling part 140 to which the abutment150 is coupled includes the first recessed part 141, the second recessedpart 142, and a screw hole 143. The first recessed part 141 is primarilyrecessed from one end of the first body 120 in the length direction ofthe first body 120. The second recessed part 142 is secondarily recesseddeeper from the other end of the first recessed part 141 in the lengthdirection of the first body 120 and has a hexagon shape. The screw hole143 is formed in a center region of the second recessed part 142 in thelength direction of the first body 120. An abutment screw (not shown) iscoupled to the screw hole 143 for coupling with the abutment 150.

The first recessed part 141 is coupled with the first coupling part 152of the abutment 150 (refer to FIG. 9). At this time, it may be necessaryto bring the first coupling part 152 of the abutment 150 into strong ortight contact with the first recessed part 141 of the first fixture 100.This is to prevent detachment and guarantee sealing for avoidinginfection. The inner wall of the first recessed part 141 is tapereddownwardly so that the diameter of the inner wall decreases from theupper side to the lower side. Like the inclined angle of the outersurface of the first coupling part 152 of the abutment 150, the inclinedangle of the inner wall of the first recessed part 141 may be in therange from 2 degrees to 6 degrees. If the inclined angle of the innerwall of the first recessed part 141 is in the above-mentioned anglerange, when the abutment 150 is coupled to the first fixture 100, thefirst coupling part 152 of the abutment 150 may be securely or tightlycoupled to the to the first recessed part 141.

The second coupling part 153 of the abutment 150 passing through thefirst recessed part 141 is coupled to the second recessed part 142 withshape matching. As shown in FIG. 9, if the second coupling part 153 ofthe abutment 150 has, for example, a hexagonal nut shape, the secondrecessed part 142 may also be formed into a hexagonal shape to have amatching shape. That is, the second recessed part 142 has a hexagonalshape, and the second coupling part 153 of the abutment 150 having thematching shape is inserted in the second recessed part 142, therebypreventing rotation of the abutment 150.

When the first coupling part 152 and the second coupling part 153 of theabutment 150 are respectively inserted in the first recessed part 141and the second recessed part 142 of the first abutment coupling part140, an abutment screw (not shown) passing through the penetration hole151 a of the abutment 150 is coupled to the screw hole 143. The screwhole 143 is manufactured to have the same size as the penetration hole151 a of the abutment 150.

Next, the first bone damage prevention part 170 and the first entranceguide part 160 formed at the opposite ends of the first body 120 aredescribed below. The first bone damage prevention part 170 is formed atone end of the first body 120 to prevent an alveolar bone existing in anopening area of the drill hole H (refer to FIG. 3) due to the firstcontinuous thread part 130 from being damaged when the first fixture 100is implanted in the drill hole H.

The first bone damage prevention part 170 is formed in a non-threadedregion where the first continuous thread part 130 is not formed, on anouter surface of the one end portion of the first body 120, to beintegrally with the first body 120 by a predetermined length at the oneend portion of the first body 120. In particular, the first bone damageprevention part 170 has a non-linear outer surface such that thediameter of the first bone damage prevention part 170 decreases from theone end portion of the first body 120 to the opposite side, asillustrated in an enlarged portion of FIG. 5.

As such, when the first bone damage prevention part 170 is provided atthe one end portion of the first body 120 in a non-threaded region wherethe first continuous thread part 130 is not formed, an alveolar boneexisting in the opening area of the drill hole H due to a thread part(not shown) formed to the one end portion of the first body 120 (thetopside portion on the drawing sheet) as in the related art may beprevented from being damaged, leading a successful implant surgery. Asillustrated in FIG. 1, a second bone damage prevention part 270 havingthe same structure and function as those of the first bone damageprevention part 170 is formed at the second fixture 200.

The first entrance guide part 160 is provided at the other end portionof the first body 120 opposite to the first bone damage prevention part170. The first entrance guide part 160 is formed as long as apredetermined section in the lengthwise direction of the first body 120from a leading end portion of the first body 120 with respect to adirection in which the first body 120 is implanted and guides the firstbody 120 in an initial implantation entrance direction.

If the first entrance guide part 160 is not formed like in the relatedart, that is, if the first continuous thread part 130 is formed even onthe first entrance guide part 160, it may be difficult to initiallyinsert the first body 120 due to the first continuous thread part 130.However, according to the present embodiment, when the first entranceguide part 160 is provided in a non-threaded region where the firstcontinuous thread part 130 is not formed, the first entrance guide part160 may be freely inserted into the drill hole H, and thus theimplantation direction may be properly kept without distortion. Then,the first fixture 100 may be implanted by using the first continuousthread part 130. Therefore, implantation may be easily performed.

As described above, the first entrance guide part 160 may be provided inthe non-threaded region where the first continuous thread part 130 isnot formed in an area of the other end portion (a lower end portion onthe drawing sheet) of the first body 120. The non-threaded region may beformed as a part of the first fixture 100 when the first fixture 100 isfabricated, or may be formed through a later process after the firstcontinuous thread part 130 is formed in the entire region of the outersurface of the first body 120. The first entrance guide part 160 may beformed from the bottom side of the first body 120 to a position of thefirst body 120 spaced upward from the bottom side of the first body 120by 1 mm to 3 mm.

The first entrance guide part 160 includes a first flat portion 161which is horizontal flat, a first inclined portion 162 extending upwardfrom a circumferential surface of the first flat portion 161 with anupwardly increasing radius, and a first rounded portion 163 connectingthe first inclined portion 162 and the first continuous thread part 130and having at least one area inwardly rounded toward the centerline ofthe first fixture 100. Unlike that shown in FIG. 4, the first roundedportion 163 and the first inclined portion 162 together form an arcline. As illustrated in FIG. 1, a second entrance guide part 260 havingthe same structure and function as those of the first entrance guidepart 160 is formed in the second fixture 200.

On the other hand, the first continuous thread part 130 is formed in aspiral shape on an outer circumferential surface of the first body 120so that the first fixture 100 may be implanted in a screw method. Thefirst continuous thread part 130 in the first fixture 100 of the presentembodiment is continuously formed on the outer surface of the first body120.

In addition, a certain section of the thread part is discontinued on theouter surface of a conventional fixture (not shown), that is, the threadpart does not continue, and one or a plurality of cutting edge portionsare formed in the lengthwise direction of the body in the area. A sharpvertical leading end portion of the cutting edge portion may cause thefixture misaligned with a fixture implantation direction.

However, in the first fixture 100 of the present embodiment, since thecutting edge portion does not exit, the first continuous thread part 130that is continuous is formed on the outer surface of the first body 120.Thus, the misalignment of the first fixture 100 with the fixtureimplantation direction due to the first continuous thread part 130 maybe prevented. In other words, the first continuous thread part 130 iscontinuously formed on the outer circumferential surface of the firstbody 120 except for the first bone damage prevention part 170 and thefirst entrance guide part 160. The same condition is applied to thesecond continuous thread part 230 of the second fixture 200. The shapeand structural characteristics of the first continuous thread part 130is described with reference to FIG. 8 with comparison with the secondcontinuous thread part 230 of the second fixture 200.

As illustrated in FIG. 8, the first continuous thread part 130 includesa first leading end part 131 a that is vertical or inclined toward oneside, a first upper curved part 131 b forming an upper surface of thefirst leading end portion 131 a, and a first lower curved part 131 cforming a lower surface of the first leading end part 131 a. In detail,the shape of a thread of the first continuous thread part 130, that is,the shape of the first continuous thread part 130 of the presentembodiment, is out of a typical shape of a triangular thread or arectangular thread and processed such that the upper and lower surfacesthereof have a convex shape, not a linear shape, with respect to thefirst leading end part 131 a.

In addition, the first leading end part 131 a has a substantiallyvertical and linear shape, whereas the upper and lower portions withrespect to the first leading end part 131 a respectively form the firstupper curved part 131 b and the second lower curved part 131 c havingupwardly and downwardly convex shapes (concave viewed from the oppositeside). Of course, any one of the first upper and lower curved parts 131b and 131 c only may be formed. However, as in the present embodiment,the first upper and lower curved parts 131 b and 131 c may be providedsymmetrically with respect to the first leading end part 131 a. Suchshape and structural characteristics may facilitate implantation of thefirst fixture 100 because a less resistance torque occurs during theimplantation of the first fixture 100.

For reference, although an angle θ between imaginary straight lines(referred to dotted lines of FIG. 8) forming the first upper and lowercurved parts 131 b and 131 c may be about 30°, the present invention isnot limited thereto. Also, although in the above the first upper andlower curved parts 131 b and 131 c are illustrated and described to besymmetrical with each other, the first upper and lower curved parts 131b and 131 c may have an asymmetrical shape. In this case, the firstlower curved part 131 c may be thicker. As a result, since it wouldsuffice that the first upper and lower curved parts 131 b and 131 cfacilitate implantation by reducing resistance torque duringimplantation of the first fixture 100, the angle between the first upperand lower curved parts 131 b and 131 c and the symmetrical orasymmetrical structure of the first upper and lower curved parts 131 band 131 c may be appropriately changed according to a situation.

The second continuous thread part 230 of the second fixture 200 also hasthe same structure as the first continuous thread part 130 of the firstfixture 100. In other words, the second continuous thread part 230 alsoincludes a second leading end part 231 a, and a second upper curved part231 c and a second lower curved part 231 c, respectively forming upperand lower surfaces of the second leading end part 231 a.

A pitch P between threads of the first continuous thread part 130 and apitch P between threads of the second continuous thread part 230 are thesame. An end portion region (a hatched portion ΔH of FIG. 8) of thesecond continuous thread part 230 is extended from the leading end part131 a of the first continuous thread part 130 further outwardly in aradius direction by a predetermined distance identically to the firstupper and lower curved parts 131 b and 131 c of the first continuousthread part 130. In the above structure, the second fixture 200 may beimplanted without additional drilling in the drill hole H (refer to FIG.3) where the first fixture 100 was implanted and also without a damageto the alveolar bone therearound. Thus implant surgery may beconveniently performed compared to the related art.

For reference, in view of a contour line of the first continuous threadpart 130, an imaginary contour line connecting the leading end portionof the first continuous thread part 130 from the first bone damageprevention part 170 to the first entrance guide part 160 forms a taperinclination line such that a width between the imaginary contour linesgradually decreases. This condition is identically applied to the secondcontinuous thread part 230. Of course, the contour lines of the firstcontinuous thread part 130 and the second continuous thread part 230 mayhave the same inclination throughout the entire area or only a partialsection may have a tapered inclination. The condition may belong to ascope of rights of the present invention.

Finally, in short, in the implant system of the present embodiment withreference to FIG. 1, the first fixture 100 and the second fixture 200have an almost common structure. In other words, the first body 120 ofthe first fixture 100 and the 220 of the second fixture 200 may bemanufactured to be identical to each other and are common in that thefirst and second entrance guide parts 160 and 260 are provided at thefirst and second bone damage prevention parts 170 and 270.

However, in comparison between the first continuous thread part 130 ofthe first fixture 100 and the second continuous thread part 230 of thesecond fixture 200, the pitch P between threads of the first continuousthread part 130 and the pitch P between threads of the second continuousthread part 230 are identical to each other, whereas they are differentin that the end portion region (the hatched portion ΔH of FIG. 8) of thesecond continuous thread part 230 is extended from the leading end part131 a of the first continuous thread part 130 further outwardly in aradius direction by a predetermined distance identically to the firstupper and lower curved parts 131 b and 131 c of the first continuousthread part 130.

Thus, as described above, since the first body 120 of the first fixture100 and the second body 220 of the second fixture 200 are equal, thedrill hole H (refer to FIG. 3) may be formed in an alveolar bone byusing the same drill (not shown). Also, when the first fixture 100 isimplanted in the drill hole H (refer to FIG. 3) formed in an alveolarbone by using a common drill as shown in FIG. 1, although implantationof the first fixture 100 fails, the second fixture 200 may be directlyimplanted in the same drill hole H without having to enlarge the drillhole H or form another hole. Therefore, dental implantation may beeasily performed as compared with the related art. This is possiblesince the first body 120 of the first fixture 100 is equal to the secondbody 220 of the second fixture 200 and only the sizes of the first andsecond continuous thread parts 130 and 230 are different from eachother.

Referring to FIG. 2, for example, when the first fixture 100 having athread diameter of 4.0 mm is implanted in the drill hole H (refer toFIG. 3) formed in an alveolar bone 13 with a common drill, althoughimplantation of the first fixture 100 fails, the second fixture 200having a thread diameter of 4.5 mm, for example, may be implanted in thesame drill hole H without additional drilling. In addition, ifimplantation of the second fixture 200 fails, third and fourth fixtureshaving thread diameters of 5.0 mm and 5.5 mm may be implanted in thesame drill hole H.

Based on the above description, an exemplary implant surgery will now beexplained. First, a drill hole H as illustrated in FIG. 3 is formed bypunching an implantation position by using a common drill (not shown).At this time, the diameter of the drill hole H may be similar or equalto a maximum width of the first body 120. Next, the first fixture 100 isplaced toward the implantation position and inserted into the drill holeH (refer to FIG. 3) of the alveolar bone 13.

When the first fixture 100 is inserted in the drill hole H (refer toFIG. 3), since the first entrance guide part 160 of the first fixture100 may be smoothly inserted in the drill hole H, the insertiondirection of the first fixture 100 may not be distorted. In other words,since the direction of initial implantation may be easily guided, theimplant surgery may be performed more easily and conveniently.

After the direction of implantation is set by the first entrance guidepart 160, the first fixture 100 is implanted while being rotated. Then,the first continuous thread part 130 structurally facilitatesimplantation of the first fixture 100. When the implantation iscompleted, the first fixture 100 is fixed to the alveolar bone with astrong fixing force. In doing so, the first bone damage prevention part170 located at the one end portion of the first fixture 100, that is, atthe topside portion on the drawing sheet, prevents the alveolar boneexisting in the opening area of the drill hole H from being damaged. Onthe other hand, although it is ideal to wait for a predetermined timeafter implanting the first fixture 100 as above, in some cases,implantation of the first fixture 100 may fail. In this case, the secondfixture 200 may be directly implanted in the drill hole H (refer to FIG.3) without additional drilling. As described above, this is possiblesince the first and second bodies 120 and 220 of the first and secondfixtures 100 and 200 are equal. In particular, this is possible sincethe pitch P between threads of the first continuous thread part 130 andthe pitch P between threads of the second continuous thread part 230 areidentical to each other, whereas they are different in that the endportion region (the hatched portion ΔH of FIG. 8) of the secondcontinuous thread part 230 is extended from the leading end part 131 aof the first continuous thread part 130 further outwardly in a radiusdirection by a predetermined distance identically to the first upper andlower curved parts 131 b and 131 c of the first continuous thread part130.

If the first fixture 100 is successfully implanted, afterosseointegration of the first fixture 100, the abutment 150 (refer toFIG. 9) is coupled to the first abutment coupling part 140 of the firstfixture 100.

When the abutment 150 is coupled to the first abutment coupling part140, the first coupling part 152 and the second coupling part 153 of theabutment 150 are inserted into and coupled to the first recessed part141 and the second recessed part 142 of the first abutment coupling part140, respectively. Then, rotation of the abutment 150 is prevented bythe coupling between the second coupling part 153 of the abutment 150and the second recessed part 142 of the first abutment coupling part140. In addition, owing to strong or tight coupling between the firstcoupling part 152 of the abutment 150 and the first recessed part 141 ofthe first abutment coupling part 140, the abutment 150 may not be easilydetached, and the possibility of infection may be reduced owing toreliable sealing formed by the strong or tight coupling.

After the first coupling part 152 and the second coupling part 153 ofthe abutment 150 are respectively inserted in the first recessed part141 and the second recessed part 142 of the first abutment coupling part140, an abutment screw (not shown) is inserted in the penetration hole151 a of the abutment 150 and is coupled to the screw hole 143 of thefirst abutment coupling part 140. Then, the implant surgery is completedby attaching a prosthesis to the abutment 150.

As described above, according to the implant system of the presentembodiment, although implantation of the first fixture 100 fails, thesecond fixture 200 may be directly implanted without additionaldrilling. Therefore, dental implantation may be conveniently performedas compared with the related art.

In addition, according to the first and second fixtures 100 and 200 fordental implants according to the present embodiment, the alveolar boneexisting in the opening area of the drill hole H may be prevented frombeing damaged due to the thread part (not shown) formed throughout theentire outer surface of the body in a conventional fixture. Thus, dentalimplantation may be performed more conveniently.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments may be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

The present invention may be applied to the field of a dental implantsurgery.

What is claimed are:
 1. A dental implant fixture comprising: a body; acontinuous thread part including a continuous thread continuously formedin a spiral shape along an outer circumferential direction of the body;a bone damage prevention part formed at one end portion of the body andpreventing an alveolar bone existing in an opening area of a hole wherethe body is implanted from being damaged due to the continuous threadpart; and an entrance guide part provided at the other end portion ofthe body and guiding the body in an initial implantation entrancedirection, wherein the entrance guide part comprises: a flat portionwhich is horizontal flat; an inclined portion extending upward from acircumferential surface of the flat portion with an upwardly increasingradius; and a rounded portion connecting the inclined portion and thecontinuous thread part and having at least one area inwardly roundedtoward the centerline of the fixture.
 2. The dental implant fixtureaccording to claim 1, wherein the bone damage prevention part isprovided in a non-threaded region where the continuous thread part isnot formed at an outer surface of an end portion of the body.
 3. Thedental implant fixture according to claim 2, wherein the bone damageprevention part is integrally formed in the body by a predeterminedlength at one end portion of the body.
 4. The dental implant fixtureaccording to claim 3, wherein the bone damage prevention part has anon-linear outer surface extending to a starting point of the continuousthread part, and has a diameter gradually decreasing along animplantation direction.
 5. The dental implant fixture according to claim1, wherein the body is provided such that an outside of the body istapered in a manner such that a diameter of the body deceases along animplantation direction, and an imaginary contour line connecting aleading end portion of the continuous thread forms a taper inclinationline such that a width between the imaginary contour lines graduallydecreases in the implantation direction.
 6. The dental implant fixtureaccording to claim 1, wherein the continuous thread comprises: a leadingend portion that is vertical or inclined toward one side; and a curvedpart formed on an upper or lower surface of the leading end portion andreducing resistance torque.
 7. The dental implant fixture according toclaim 6, wherein the curved part is an upper or lower curved partrespectively formed on an upper or lower surface with respect to theleading end portion.
 8. The dental implant fixture according to claim 1,wherein an abutment coupling part to which an abutment is coupled isprovided in an inner area of one end portion of the body, and theabutment coupling part comprises: a first recessed part primarilyrecessed from one end of the body in a length direction of the body; asecond recessed part secondarily recessed deeper from the other end ofthe first recessed part in the length direction of the body and has apolygonal shape; and a screw hole formed in a center region of thesecond recessed part in the length direction of the body, to which anabutment screw for coupling with the abutment is coupled.